We shall study interrelationships among human growth hormone (hGH), Factor VIII and diabetes mellitus as a basis for understanding macrovascular disease as a possible proliferative disorder. HGH will be studied as a family of proteins--S-S dimer, intact forms (20K and newer forms) and cleaved or 2-chain forms. Studies will include radioimmunoassays, radioreceptor, and bioassays. Stimuli to hGH release will be mainly sleep and exercise--as physiological stimuli. Endothelial cells will be cultured with forms of hGH and Factor VIII production studied. The glycosylation of Factor VIII in respect to diabetes will be studied. Platelet membranes in normal and diabetic subjects will be compared by spin resonance techniques. Pituitary peptides as direct insulin secretagogues will be studied using isolated islets of hypophysectomized rats.